Quantum Entanglement
by ScientificHufflepuff
Summary: The instantaneous connection between two particles, kept no matter the distance between them. When Doc and Marty's return from 1885 goes exactly as planned, a teacher with everything to gain is left behind to track down the future. While one hundred years away, an inventor with everything already lost struggles to let go of the past. AU, post-trilogy, might get angsty.
1. Crash

An explosion and a trail of fire broke the otherwise utter stillness of the scene: an ordinary railroad crossing on a sleepy morning. The cause of the disruption was a dirty and damaged silver vehicle, rolling from top speed to whining stop after appearing there out of thin air. The car's occupants sat there, wide-eyed and allowing themselves to breathe, after having been waiting to do so almost more than a minute before they'd appeared. They were back. It was over. Except, like all things that just seemed to keep on happening, like the past couple weeks had seemed to do, it actually wasn't. The second interruption to the silence was a moving train, churning down the track with no intention of letting up for the sake of that sad little car. Reaction times realized they were still needed, albeit begrudgingly, and the two male passengers, one old, one young, scrambled to throw open the gull-wing doors, and threw themselves out onto the ground as quickly as possible to avoid the oncoming tons of steel and heat, which in the very next moment tore through the DeLorean on the tracks as though it were little more than an empty can.

The train passed, and the two worn travelers spotted each other across the tracks. Each wore an expression that seemed a mirror to the other's emotion. Mostly shock.

Marty, the younger one, pushed himself to his feet first, stumbled, and made his way forwards.

Doc, the elder, seemed to have just remembered he had feet, and was working out how to use them by experimentation. They met at the center, at the tracks, looking at the wreckage. The car had been rendered to little more than scrap withing the span of those few seconds. A few pieces could be recognized, but not many. A wheel trying to make an escape finally fell over, at a surprisingly successful distance away. The electric time display sparked and blinked nothing but '8's in every readout, and was cracked in half and holding together by just a few wires. The Flux Capacitor lay between its inventors' feet, sparking, smoking, as a moment later, it died.

Marty took a step back, shaking his head, fingers curled up in his hair. "Jesus Christ, Doc..." He said, voice choked in how overwhelming, how very nearly and how many different ways they had both nearly been killed that morning. And it wasn't even that morning anymore! He didn't have the energy for fourth-dimensional correctness, and he knew this just as much as he knew it was getting close to the last straw of his recent stresses.

Doc, meanwhile, was beginning to look much less shaken and much more set. Well, this saved him a step later, though he hadn't expected it to have been so sudden.

"Doc..." Began Marty, as though about to apologize to, or perhaps console his friend.

"I said I wanted it destroyed when we got back." Doc said, simply. "This machine has cause more trouble than I could ever have bargained for." With his shoe, he turned over the burnt-out capacitor to face upwards. It was only a small, lifelong dream, after all...

"No kidding." Said Marty, who'd been on the brunt end of said troubles over the past few weeks. "So, ah, Doc... What... What do we do now?"

"Go home." The scientist's tension seemed to start to slip away, though he still kept himself upright in the sort of way which meant he still had work to do. "Find Einstein, and Jennifer, and make sure nothing's changed during our last trip to the past."

Marty's eyes went wide. "Jennifer!" He exclaimed. "Do you think she'll be...?"

"To the best of my understanding, Miss Parker should be just as we left her. Asleep, and unharmed. But I'd still check, if I were you."

"Thank God." Breathed Marty, then looked up at his friend.

"Go on ahead. I'll meet with you later. I'm going to stay here for a little while longer."

"Why?"

"Oh, salvage a few things before someone else finds them. Destroying a time machine only to leave the key components lying in plain sight would defeat the purpose. I'm sure I'll see you shortly, Marty."

Marty nodded his thanks, looked around for his bearings, and then set off at a quick pace after his girlfriend.

Doc, then, was left with the wreckage. He pocketed his hands, surveying out and around the scattered car parts, and sighed. It was over. After thirty years, completely, totally, and finally over. He was hit with a wash of release, and something like tiredness. Understandable, given how his morning had gone up til then. Misery, unconsciousness, sudden sobriety, duels, theft, fast-paced maneuvering and time travel. It was enough to do a number on any man. But, as always, 'over' came with clean-up. He picked up the Flux Capacitor, tucked it under one arm, and went for the time circuits. Their own weight caused the console to finally snap when he picked it up, cutting out the flickering light and causing half the readout to fall back on the ground.

Satisfied with having picked up most of the pieces, namely the circuits, and the heart of the time machine, plus the fusion generator, (he'd come back for the wheels and the rest, the former of which he'd kicked out of sight under a bush,) he made his way back home, hardly wondering himself at what would come next.

[Y]

Clara rode like her life depended on it along the train tracks. In a way, it sort of did. The night before, she'd scorned the blacksmith for toying with her, using her loves and dreams to mock her. There was no real way what he was saying could possibly be true, though, oh, how she would have loved that it was. That the man she'd fallen for was both honest, and really _had_ come from the future, and been willing to take her there with him. The events of this morning, however, had turned her doubts around entirely. Had she judged too soon? And would she be too late to fix it now?

The diorama in Emmett's workshop had given her a map for his plan, if it was really true. She wanted it to be true, and with her concentrated on staying on her horse, she simply didn't have the mental space to share for any other option.

There was the train! She urged her horse on faster, getting to within a couple yards of the back cab. Just then, something exploded near the front, dousing her in an unnaturally colored smoke. The train pulled away from her, moving faster, louder now. Clara sped up in kind, but felt her heart sink as she continued to lose ground. No... She thought she could see someone in the conductor's cab, someone with distinctive silver hair leaning out of the window. She called after him, but it proved to be no use. There was too much noise, too much speed, and her horse, she could feel, was starting to tire under her. She yelled again as another explosion rocked the train, leaving her coughing from a new color of smoke. Clara urged her horse, but the poor beast had had enough urging for one day. It trotted, whinnying its annoyance at her as she watched the train, that ticket to wonder, slip from sight. Her mind was in a blank sort of state, berating herself for both the wild goose change, and for not beginning it sooner. It couldn't be true... _It wasn't, and she'd lost it... Oh, lost it, yes, certainly she'd lost her m-..._

BOOM!

Clara shot upright in her seat. The horse gave a nervous whinny, and suggested moving in the other direction. She reined it in. The whole area had gone quiet, suddenly, after that noise, and she dared not think as to what it meant. Had he really done it?

She continued down the track, now at a far less breakneck pace, keeping an eye out for any indication as to what had happened. She stopped a ways short from the end of the line, staring ahead in horror. No track, no train, just an unfinished bridge over a gaping ravine. She dismounted, preferring to be on her own two feet, so near to the edge for the second tune in nearly as many days, and went only close enough to be able to stand back with her hand over her mouth and still see the colossal locomotive wreck lying at the bottom, giving off three colors of smoke. She had to go down there! She had to see for herself, she had to-... She had to be reasonable about this. There was only one way down, from where she stood, which meant no getting back up again. Ever. Perhaps this wreck was the plan? Perhaps, but she couldn't see why... The time machine had been a unique object in the model, though, so perhaps it was? There was no way to know. Logic aside, though, she still felt sick, and restless. She had to know. Like nothing else in the world she had to know what had occurred when the train went out of sight. But there was nothing-... No. No 'nothing' to investigate. Clara went back to her horse, gave it a determined pat, and hopped back on. She'd see the Sheriff about this. He'd have a search party. _Someone_ would have to clean it all up after all, and she'd go with them, unsure of what to look for, but just as sure she'd know if she found it. A time machine would have to look different from a train, wouldn't it?


	2. Salvage (Part 1)

It hadn't taken long for Sheriff Strickland to organize a search party, once Clara had explained what had happened. He'd insisted she not go with them, as train wrecks were horrendous things and she's been through enough already. She insisted on going anyway, seeing as how she'd been the one to find it in the first place, and after recent experiences, it would take an awful lot more than wrecked metal to scare her. She did concede, though, to standing back a ways while the searchers made their first pass through. McFly had been calm, and kind in pulling her away by the shoulder and gently made a case for waiting. He'd been hesitant to strictly say "bodies", but Clara picked up his meaning quickly. If Emmett and Clint were still down there... She wanted to know, as soon as was possible, but perhaps she didn't want to see. Gone in one sense was hard enough.

The sun crept slowly across the sky, and Clara sat on a rock, watching the dozen or so men who'd volunteered to help in the last hurrah of summer heat a little distance away. So far, they'd found nothing you wouldn't expect from a locomotive engine, and had retrieved and set aside most of the usable or useful pieces. They'd identified the train, and Strickland was making arrangements to find and talk with the former conductor with one of the younger volunteers, who left past Clara once they'd finished with that they were doing.

"Excuse me!" She called, standing up. She didn't especially recognize the fellow, but she felt she had seen him around the town,or perhaps among the blur of faces that had attended to festival, which, she assumed, was pretty much the whole town.

"Yes, Ma'am?" He wheeled his horse around to be able to see her.

"Have they found anything?" She asked, politely as she could, but with a tingle of anxiety. She really _was_ too far to see much of anything.

"No, Ma'am. She shook his head. "Unless you mean train, in which case, we've found a LOT of that, scattered all over the place, too! And no wonder... What kinda lunatic just sends an empty train off a bridge after goin' to the trouble of stealing it?"

Someone, perhaps, with a time machine, trapped in a year far more primitive than the time he'd known. Clara's heart pulled just thinking about it again, but she kept her thoughts to herself. "It was definitely empty?" She asked, hopefully.

"Well..." Said the man, scratching under his hat "We haven't found hide or hair that anybody was ever in there, but you can't count out John Lathrop swore he saw a bear around here a lil while back."

"I see..." Said Clara. "Well, thank you, you should be going I suppose. I don't mean to hold you up."

"No trouble ma'am. You sure you don't want to go back?"

"Not yet, thank you." Clara watched horse and rider follow the ravine path around a bend and out of sight. It was a long ways back up to either side. She stood up, smoothed down her skirts, and headed over to the crash site. She got some odd looks, stepping in and around the sorted piles of train parts, and was even urged a few times to go and stand back again, or even go home, a train wreck wasn't a place for a lady after all.

"It's only metal." She reasoned back, "and it's not like I'll be left afraid of trains afterward, I really don't plan to ride any that are scheduled to go off an unfinished track."

There was some murmuring, and then a general consensus that she made a point. She didn't seem shocked or shaken, only curious and determined. Some suggested she still may not want to be out in this weather, but those, like Seamus, who were married, argued that work and weather wouldn't hurt her more than it would anyone else. Still... Said others, she was only a young teacher, from a city life on the East Coast up til the past month or so.

Clara however, didn't hear nor care about any of their debating. Merely picking through the scrap for... She didn't know what, but assumed she could recognize any parts of machinery built 100 years from now But even if she could, she found nothing. She saw the boiler stained with tri-colored soot, other pieces clearly identifiable as 'train', but little that was otherwise unique.

"What d'ya suppose this'd be? Came Seamus's voice across the flat stretch. Clara shot up, and turned around.

The farmer held a small black box, with a wire sticking out the top and a sort of grating on the front. He pressed a button on the side, and it made a loud, scratchy, 'chok' noise, which made everyone who'd gathered near him to see, jump. He tried it a couple more times, until no one was surprised by the sound any more. "I can't see the use of it." He admitted, turning it over a couple times before passing it around. Clara had just arrived at the clump of curious people, and soon held the device before anyone was able to question whether she should.

It was a strange sort of smooth, shining material, not quite glass or painted wood or metal. Clara turned it over. The words "Walkie Talkie" were painted on the front in faded scuffed letters, and her heart skipped a beat when she saw it, the number 1982 printed in even smaller, raised type near a panel on the back. She tries to keep her expression neutral. "Could I have this?" She asked Strickland, holding it up as he came up from behind.

There was some non-committal murmuring, and then, "I don't see why not." He nodded at her. "We'll ask the conductor about it and see what he knows. But for now, you can hold onto it."

Cara nodded, holding the box, that artifact from the future, closely. "Thank you." She said, then looked about herself. "I think I may leave, now. Would you please tell me if you find anything else strange, like this?"

A tip of the hat. "Will do, Miss. I don't see why you're interested."

"I just think it's fascinating." Not entirely untrue. The people she'd seen her with the blacksmith, Brown, at the festival, exchanged knowing looks. It really _was_ no wonder that those two had hit it off so well.

Seamus took it upon himself to escort Clara back up the ravine and back to her home. She didn't mind him, or care all that much either way, too lost in her own schemes and plans for her return. She's find out what the little gadget did, if she could, and then search every trace of Emmett's workshop for answers. Failing that, she would ask around about him, any strange projects of events that could lead her to bringing him back to her time, or perhaps, herself to his.

* * *

 **And now, a note from the author:**

Hello there! Very, VERY sorry about how long this's taken! Typing up documents from handwriting is a real pain, and I've written a bit more than what's here and should have it up sooner than later. I meant to get this (plus a bit more) out this _past_ Tuesday, but life and power outages made that tricky. Ergo, I'm going ahead and posting the first part of this chapter early for you guys! The next (Doc-focused) chap I hope to put up over the weekend, and HOPEFULLY try and move towards my goal of weekly updates. So while this one's short, the next one will definitely be a little longer.

Thank you _so much_ to those who have left feedback already! It's like getting a fuzzy blanket out of the dryer, expect via email! :D


	3. Salvage (Part 2)

It was the slow, sunny part of the middle of the day. Preferably, he would have been there at nighttime, there the gleaming metal and white van would not have been quite so conspicuous. But despite his hurrying and bated breathing, frantic glances over the shoulder and broad daylight, one came to bother him, and no one even passed by the old traintacks. Besides, it wasn't as if he could have have let the job go a minute longer than it already had. Barely an hour had passed since his and Marty's return, but that might have been time enough for someone to have seen the wreckage, and called it to question. But again, Doc reassured himself, that he was entirely _alone_ at his work.

Marty was-... Well, it was entirely possible that he could have offered his help, had he asked, but calling him up would have just taken more time that could instead be then put towards getting rid of the mess of the DeLorean sooner. And it wasn't like the old inventor didn't have enough energy for two people anyway... Best leave to boy to recoup. He'd had enough adventures to fill over a year without dragging him away from home once more. Einstein, too, despite sad whining and every possible effort of loveability, had been left behind. He didn't feel like pulling glass and metal shards from the sheepdog's pawpads today, and figured his pet would be of the same mind, had he understood the brief explanation he'd given to him before barrelling right back out the minute he'd changed into more period-appropriate attire.

Despite his concerns for the other two, though, he was staring to feel some of their would-be troubles himself. After months in the past, he's sort of... Forgotten... Where he'd put his good work gloves in the present. His forge-calloused hand had picked up a remarkable number of small scratches and other nicks as he picked up the pieces and tossed them loosely into the back of the van, where they gave a hollow clanging echo on the inside (he had no doubt in his mind it would all fit into there comfortably, since it's housed the _whole_ car, once, with no trouble at all). He was also starting to move a little slower than he was hoping for. He hadn't really taken into account the events of the previous morning, and what effect they might have on him. Fighting off Tannen's gang of bandits, stealing a train, scaling across the top of it as it approached 90MPH... It was thrilling, and he'd come out standing, but he felt his eyes begin to want to cross as he searched out every scrap of bolt that had been flung into the first by the force of the impact.

So, it was later, and with slightly more irritation, that he decided the place had been sufficiently cleared of all scraps of former time-machine, and hauled himself into the driver's side of his van. With a switch-flick, the back of the vehicle rumbled closed, and Doc revved the heavy engine and drove off, finally letting himself sigh once again. Now everything was safely in the back, and he didn't have to worry about it, a least for a little while or so. Within a week, he suspected, he's have everything unpacked, looked over, salvaged where possible, and sorted away into scrap for use on a new project. He'd absently tapped a fidgety non-rhythm on the top of the steering wheel, as he'd come to a stop at a red light. Yes, one week sounded about right... He gave a darkly amused huff as he thought of it. Thirty years, from concept to completion, and seven days or less to take it all to pieces again. An entire inheritance sunk into one project, soon to pan out to nothing more than a half dozen boxes or so of so many spare parts. He could possibly sell he metal hull of the car, but knowing himself, he'd come into a need for it sooner or later. It would hardly be worth the trouble, and cost him in the end to boot. Science was made of failures, and he suppose he could be lucky this one ended up as a supply run that'd last him probably a few years, on various continued inventions. At least this time nothing had been lost to fire.

The light changed, and he coaxed the engine to try and get momentum going again. He hadn't thought much about his own work past finishing the time machine. He had a few old small thing stowed away in his notebook he'd written down at unreasonable hours of the morning, but nothing so grand as what he currently was hauling away. He mulled over the ones he was currently able to recall on the way back to the garage, and had become rather distant by the time he stepped his way through the door. Einstein padded over when he'd heard the lock click, and was greeted by a rough head-pat and affectionate mumbling. The dog gave a sniff of concern to his owner's hands, which caused Doc to wince slightly, pulling him back to reality. "Hey, there..." He hummed, kneeling down to the dog's level for some more attentive scratches, and then straightened himself up awkwardly, placing his feet down in a few different places to find the best balance. Well then... He turned his hands over in front of his face for a moment or so, then headed for the sinck to wash them.

Meanwhile, a hundred plus clocks began to ring, ding, hoot squeak, beep, or bong out the hour. He stopped with his hands in the water, looking up. It'd been _months_ since he'd heard that sound, and, indeed, months since he thought he ever would again. It was... Comforting, in a way, but not so much as he would have expected. More than anything, it made the past near-year of his life feel like something out of a dream. A nightmare in some respects, perhaps, but... He'd been more than willing to have simply remained in the past, and forgotten all that had happened somewhere entirely different. Or, well, some _when_ , at any rate. The fledgling town of Hill Valley was still recognizable, in many places, but a hundred years could still make it dreadfully easy to forget.

The clocks were wrapping up their chiming as Doc crossed the floor of his living space once again, Einstein padding lightly after him with his usual curious interest. The inventor stopped, backtracked, and then headed the other way, dog following obligingly after. This continued for a few more laps around the main space of the garage, Emmett careful to step around the remains of the giant amplifier and bookshelf, before he swept with a little more decided purpose towards a small end-table drawer. The battered notebook in it might as well have been half scrapbook. Notes, doodles, and back of the envelope calculations were, in fact, written on envelopes, notecards, napkins, a bill or two, really, whatever papery object had been close to hand at the time. Sometimes, that object was even the pages of the book itself. It was about a year's worth of miscellaneous ideas, and the book had taken a merciless beating despite its' relatively short life.

Emmett skimmed inwards a handful of pages, recalling distinctly (or sometimes not at all) the times and places he'd written everything down, and, sometimes, what the Hell he'd even been _thinking_ when he'd done so. He let himself drop into a worn armchair and crossed one leg over the other, not looking up from his reading. No, no... Not this, not that... He got to the end of the pages, and then started over again, this time noticing a few scrap pieces of paper that'd fallen out of the book and onto his lap. There was no shortage of _little_ ideas, but they were all simply that. _Underwhelming_. He needed something that was a good _challenge_. That could grab his attention and hold it for a little while. Something able to take his mind off of the whole-... He sighed. ... _Mess_ , he'd created and then so nearly dearly paid for.

Clearly, though, his mind in this past year had had room for only _one_ large project, and so with mild annoyance he got himself up and fetched a cardboard office box from under a table. Inside, were the dustier and, if at all possible, _worser_ -kept cousins of his current ideas journal. Thoughtfully, he picked up one with a questionably black-crisped edge to the pages, and returned with it to his chair. He expected it had seen a lot, quickly trying to remember what time it'd belonged to as he pulled up the inside cover. At a slight slant to the horizontal, his full name and honorific were written in a neat, blue cursive, along with his address and the month and year he'd first started using the book. Ah, yes... '81. That'd been before Marty had arrived, reminding him of the deadline he would have to work out over the next few years. With a pang, he wondered if his original timeline's self might have created a better version of the car, if he'd started earlier or felt less rushed. One that-... Nah. The problems with the time machine were simply inherent to the concept. Although, perhaps, his other self might have taken changing the future with a little more _care._..

He shook his head. No. The past, and the future for that matter, were going to stay precisely where they belonged, and it was hardly any use considering eithe now. _New_ project, new start, everything back to how it had been before. Minus that one, enormous, looming project of three decades. It'd be fun. He could _finally_ do as many as half the things he'd written down, maybe even finish a quarter of them within his newly extended life expectancy.

He could do those later. Doc hopped to his feet, unable to focus on the scratchy notes of a distracted tinkerer. He set the books by the floor of the chair, and moved over to the disaster area that was the middle of the room. For once, this one wasn't entirely his fault. Hadn't he warned Marty about the chance of overload? He could have sworn he had, but it'd been half a year ago after all...

The inventor sprang off again, this time in search of spare office boxes in the overstuffed storage closet at the back of the garage. He found a few (and made a mental note to have Marty pick up more, he'd be needing them later for the car) and popped them smoothly into shape. He kicked one directly over the the base of the mess, and then carried the others under his arms and on his head. If the _lab_ were cleaned, he surmised, he'd quickly find some way to drive the process of entropy in it forwards once again, with some scattered and fervent scheme. It had always happened that way, and there was no reason for such a tried-and-true pattern to not hold once again.

It was simple science.


End file.
